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Active, not recruitingNCT06686654Updated Dec 11, 2025

Study of a Human Metapneumovirus/Respiratory Syncytial Virus mRNA Vaccine Candidate Encapsulated in a Lipid Nanoparticle-based Formulation in Adults Aged 60 Years and Older

A Phase 1/2 interventional study of Investigational hMPV/RSV vaccine and Investigational hMPV vaccine (monovalent) in Human Metapneumovirus Immunization and Respiratory Syncytial Virus Immunization, sponsored by Sanofi Pasteur, a Sanofi Company. Active, not recruiting at 24 sites in United States. Open to participants aged 60 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-12-11.

Sponsored by Sanofi Pasteur, a Sanofi Company · Phase 1/2, Interventional, and Prevention

Phase
Phase 1/2
Study type
Interventional
Enrollment
1,530
Allocation
Randomized
Ages
60 Years and older
Sex
All
01

Study summary

The aim of this study is to evaluate the safety and immunogenicity of a human metapneumovirus (hMPV) / respiratory syncytial virus (RSV) mRNA vaccine candidate encapsulated in a lipid nanoparticle (LNP) based formulation (hereafter referred to as hMPV/RSV vaccine) for the prevention of lower respiratory tract disease (LRTD) caused by hMPV and/or RSV among adults aged 60 years and older.

The study will also evaluate the safety and immunogenicity of a booster vaccination using a bivalent hMPV/RSV mRNA vaccine candidate (hereafter referred to as RSV+hMPV mRNA vaccine candidate).

Overall, the study is designed to address the following goals:

  • Assess the safety profile of the candidate formulations.
  • Describe the immunogenicity profile of the candidate formulations.
  • Select the vaccine formulations (dose) for future development.
  • Assess the safety and immunogenicity of a booster vaccination with the RSV + hMPV mRNA vaccine candidate administered 12 months after primary vaccination with a licensed RSV vaccine.

The study duration is as follows:

-Six months each for the Sentinel and Main Cohorts; up to 12 months for the Expansion Cohort, and 6 additional months for the Booster Cohort

Treatment duration:

  • Stage 1 Sentinel Cohort: 1 intra-muscular (IM) injection. Participants will be followed for 6 months post vaccination
  • Stage 1 Main Cohort: 1 IM injection. Participants will be followed for 6 months post vaccination
  • Stage 2 Expansion Cohort: 1 IM injection. Participants in the licensed RSV vaccine arm will be followed for 12 months post-vaccination; the remainder of the participants will be followed up to 8 months post-vaccination
  • Stage 2 Booster Cohort: 1 IM injection 12 months post-primary vaccination. Participants will be followed for 6 months post-booster vaccination
02

Conditions studied

  • Human Metapneumovirus Immunization
  • Respiratory Syncytial Virus Immunization

Keywords

  • hMPV
  • RSV
  • respiratory syncytial virus infection
  • human metapneumovirus infection
03

In context

Respiratory Syncytial Virus Infections

293 studies on the registry are indexed under Respiratory Syncytial Virus Infections; 45 are open to participants now.

This study's enrollment of 1,530 is above the median of 90 across 213 interventional studies indexed under Respiratory Syncytial Virus Infections.

Browse Respiratory Syncytial Virus Infections studies →

Lead sponsor

Sanofi Pasteur, a Sanofi Company is the lead sponsor of 366 studies on the registry; 4 are open to participants now.

Of its 94 completed or terminated interventional studies of FDA-regulated products, 73 (78%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
60 Years and older
Sexes eligible
All
Accepts healthy volunteers
Yes

Inclusion criteria

  • Aged 60 years or older on the day of inclusion
  • A female participant is eligible to participate if she is not pregnant or breastfeeding and is of non-childbearing potential. To be considered of non-childbearing potential, a female must be postmenopausal for at least 1 year or surgically sterile

Exclusion criteria

Exclusion Criteria:

  • Any screening laboratory parameter with laboratory abnormality > Grade 1 deemed clinically significant by the investigator
  • Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy, within the preceding 6 months; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks within the past 3 months). Of note, persons living with stable human immunodeficiency virus (HIV) are not excluded
  • Known systemic hypersensitivity to any of the study intervention components (eg, polyethylene glycol, polysorbate); history of a life-threatening reaction to the study interventions used in the study or to a product containing any of the same substances; any allergic reaction (eg, anaphylaxis) after administration of an mRNA vaccine
  • History of RSV and/or hMPV-associated illness, diagnosed serologically or microbiologically in the last 12 months
  • Previous history of myocarditis, pericarditis, and/or myopericarditis
  • Screening electrocardiogram that is consistent with possible myocarditis, pericarditis, and/or myopericarditis or, in the opinion of the investigator, demonstrates clinically relevant abnormalities that may affect participant safety or study results
  • Laboratory-confirmed thrombocytopenia, contraindicating IM injection, based on investigator's judgment
  • Bleeding disorder or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating IM injection, based on investigator's judgment
  • Chronic illness that, in the opinion of the investigator, is at a stage where it might interfere with study conduct or completion
  • Receipt of any vaccine other than mRNA vaccine in the 28 days preceding any study intervention administration or planned receipt of any vaccine other than mRNA vaccine in the 28 days following any study intervention administration
  • Receipt of any mRNA vaccine in the 60 days preceding any study intervention administration or planned receipt of any mRNA vaccine in the 60 days following any study intervention administration
  • Previous vaccination against RSV and/or hMPV (with a licensed or investigational vaccine either as a monovalent vaccine or any combination of the antigens)
  • Receipt of immune globulins, blood, or blood-derived products in the past 3 months

Note: The above information is not intended to contain all considerations relevant to a potential participation in a clinical trial.

05

Study design

Phase
Phase 1 / Phase 2
Primary purpose
Prevention
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Quadruple (Participant, Care provider, Investigator, Outcomes assessor)
Enrollment
1,530 participants (actual)

Study arms

  • Experimental
    Group A Stage 1 Sentinel Cohort

    1 IM injection of investigational hMPV/RSV vaccine formulation A

    Biological: Investigational hMPV/RSV vaccine

  • Experimental
    Group B Stage 1 Sentinel Cohort

    1 IM injection of investigational hMPV/RSV vaccine formulation B

    Biological: Investigational hMPV/RSV vaccine

  • Placebo comparator
    Group C Stage 1 Sentinel Cohort

    1 IM injection of placebo

    Biological: Placebo

  • Experimental
    Group 1 Stage 1 Main Cohort

    1 IM injection of investigational hMPV/RSV vaccine formulation C

    Biological: Investigational hMPV/RSV vaccine

  • Experimental
    Group 2 Stage 1 Main Cohort

    1 IM injection of investigational hMPV/RSV vaccine formulation D

    Biological: Investigational hMPV/RSV vaccine

  • Experimental
    Group 3 Stage 1 Main Cohort

    1 IM injection of investigational hMPV/RSV vaccine formulation E

    Biological: Investigational hMPV/RSV vaccine

  • Experimental
    Group 4 Stage 1 Main Cohort

    1 IM injection of investigational hMPV/RSV vaccine formulation F

    Biological: Investigational hMPV/RSV vaccine

  • Experimental
    Group 5 Stage 1 Main Cohort

    1 IM injection of investigational hMPV/RSV vaccine formulation G

    Biological: Investigational hMPV/RSV vaccine

  • Experimental
    Group 6 Stage 1 Main Cohort

    1 IM injection of investigational hMPV/RSV vaccine formulation A

    Biological: Investigational hMPV/RSV vaccine

  • Experimental
    Group 7 Stage 1 Main Cohort

    1 IM injection of investigational hMPV/RSV vaccine formulation B

    Biological: Investigational hMPV/RSV vaccine

  • Experimental
    Group 8 Stage 1 Main Cohort

    1 IM injection of investigational hMPV/RSV vaccine formulation H

    Biological: Investigational hMPV/RSV vaccine

  • Experimental
    Group 9 Stage 1 Main Cohort

    1 IM injection of investigational hMPV/RSV vaccine formulation I

    Biological: Investigational hMPV/RSV vaccine

  • Experimental
    Group 10 Stage 1 Main Cohort

    1 IM injection of investigational hMPV/RSV vaccine formulation J

    Biological: Investigational hMPV/RSV vaccine

  • Placebo comparator
    Group 11 Stage 1 Main Cohort

    1 IM injection of placebo

    Biological: Placebo

  • Experimental
    Group X Stage 2 Expansion Cohort

    1 IM injection of selected investigational hMPV/RSV vaccine formulation from Group 1-9 of Stage 1 Main Cohort

    Biological: Investigational hMPV/RSV vaccine

  • Experimental
    Group 12 Stage 2 Expansion Cohort

    1 IM injection of investigational RSV monovalent vaccine

    Biological: Investigational RSV vaccine (monovalent)

  • Experimental
    Group 13 Stage 2 Expansion Cohort

    1 IM injection of investigational hMPV monovalent vaccine

    Biological: Investigational hMPV vaccine (monovalent)

  • Experimental
    Group 14 Stage 2 Expansion Cohort

    1 IM injection of licensed RSV vaccine

    Biological: Licensed RSV Vaccine

  • Experimental
    Group 15 Stage 2 Booster Cohort

    1 IM injection of investigational RSV + hMPV vaccine formulation administered to participants from Group 14 of Expansion Cohort

    Biological: Investigational hMPV/RSV vaccine · Biological: Investigational RSV+hMPV vaccine

Interventions

  • BiologicalInvestigational hMPV/RSV vaccine

    Investigational hMPV/RSV vaccine administered intramuscularly

  • BiologicalInvestigational hMPV vaccine (monovalent)

    Investigational hMPV vaccine (monovalent) administered intramuscularly

  • BiologicalInvestigational RSV vaccine (monovalent)

    Investigational RSV vaccine (monovalent) administered intramuscularly

  • BiologicalLicensed RSV Vaccine

    Licensed RSV vaccine administered intramuscularly

  • BiologicalPlacebo

    Placebo administered intramuscularly

  • BiologicalInvestigational RSV+hMPV vaccine

    Investigational RSV+hMPV vaccine administered intramuscularly

06

What researchers measure

Primary outcomes

  1. Presence of unsolicited immediate systemic adverse events (AEs) (Stage 1 and Stage 2 Expansion and Booster Cohorts)

    Number of participants reporting immediate unsolicited systemic AEs

    Time frame: Within 30 minutes after primary and booster vaccinations

  2. Presence of solicited injection site and systemic reactions (Stage 1 and Stage 2 Expansion and Booster Cohorts)

    Number of participants reporting solicited injection site and systemic reactions

    Time frame: Up to 7 days after primary and booster vaccinations

  3. Presence of unsolicited AEs (Stage 1 and Stage 2 Expansion and Booster Cohorts)

    Number of participants reporting unsolicited AEs

    Time frame: Up to 28 days after primary and booster vaccinations

  4. Presence of medically attended AEs (MAAEs) (Stage 1 and Stage 2 Expansion and Booster Cohorts)

    Number of participants reporting MAAEs

    Time frame: Up to 6 months after primary and booster vaccinations

  5. Presence of serious AEs (SAEs) and AEs of special interest (AESIs) (Stage 1 and Stage 2 Expansion and Booster Cohorts)

    Number of participants reporting SAEs and AESIs

    Time frame: Up to 6 months after primary and booster vaccinations

  6. Presence of related SAEs, related AESIs, and fatal SAEs (regardless of causality) (Stage 1 and Stage 2 Expansion and Booster Cohorts)

    Number of participants reporting related SAEs, related AESIs, and fatal SAEs

    Time frame: Throughout the duration of the study (up to approximately 24 months)

  7. Presence of out-of-range biological test results (Stage 1)

    Number of participants with out-of-range biological tests

    Time frame: Up to 7 days after primary vaccination

  8. Presence of out-of-range biological test results (Stage 2 Booster Cohort)

    Number of participants with out-of-range biological tests

    Time frame: Up to 7 days after booster vaccination

  9. hMPV A serum neutralizing antibodies (nAb) titers in Stage 1 Sentinel and Main Cohorts

    nAb titers expressed as geometric mean titers (GMTs)

    Time frame: At pre-vaccination (Day 01) and 28 days post-primary vaccination (Day 29)

  10. hMPV B serum neutralizing antibodies (nAb) titers in Stage 1 Sentinel and Main Cohorts

    nAb titers expressed as geometric mean titers (GMTs)

    Time frame: At pre-vaccination (Day 01) and 28 days post-primary vaccination (Day 29)

  11. RSV A serum nAb titers in Stage 1 Sentinel and Main Cohorts

    nAb titers expressed as geometric mean titers (GMTs)

    Time frame: At pre vaccination (D01) and 28 days post-primary vaccination (D29)

  12. RSV B serum nAb titers in Stage 1 Sentinel and Main Cohorts

    nAb titers expressed as geometric mean titers (GMTs)

    Time frame: At pre vaccination (D01) and 28 days post-primary vaccination (D29)

  13. hMPV A serum neutralizing antibodies (nAb) titers in Stage 2 Expansion Chort

    nAb titers expressed as geometric mean titers (GMTs)

    Time frame: At (Day 01) pre-vaccination and 28 days after the injection of the hMPV/RSV vaccine candidate (Day 29)

  14. hMPV B serum neutralizing antibodies (nAb) titers in Stage 2 Expansion Chort

    nAb titers expressed as geometric mean titers (GMTs)

    Time frame: At (Day 01) pre-vaccination and 28 days after the injection of the hMPV/RSV vaccine candidate (Day 29)

  15. RSV A serum neutralizing antibodies (nAb) titers in Stage 2 Expansion Chort

    nAb titers expressed as geometric mean titers (GMTs)

    Time frame: At (Day 01) pre-vaccination and 28 days after the injection of the hMPV/RSV vaccine candidate (Day 29)

  16. RSV B serum neutralizing antibodies (nAb) titers in Stage 2 Expansion Chort

    nAb titers expressed as geometric mean titers (GMTs)

    Time frame: At (Day 01) pre-vaccination and 28 days after the injection of the hMPV/RSV vaccine candidate (Day 29)

  17. hMPV A serum neutralizing antibodies (nAb) titers in Stage 2 Expansion Chort

    nAb titers expressed as geometric mean titers (GMTs)

    Time frame: At (Day 01) pre-vaccination and 28 days after the injection of the hMPV standalone vaccine (Day 29)

  18. hMPV B serum neutralizing antibodies (nAb) titers in Stage 2 Expansion Chort

    nAb titers expressed as geometric mean titers (GMTs)

    Time frame: At (Day 01) pre-vaccination and 28 days after the injection of the hMPV standalone vaccine (Day 29)

  19. RSV A serum neutralizing antibodies (nAb) titers in Stage 2 Expansion Chort

    nAb titers expressed as geometric mean titers (GMTs)

    Time frame: At (Day 01) pre-vaccination and 28 days after the injection of the RSV standalone vaccine (Day 29)

  20. RSV B serum neutralizing antibodies (nAb) titers in Stage 2 Expansion Chort

    nAb titers expressed as geometric mean titers (GMTs)

    Time frame: At (Day 01) pre-vaccination and 28 days after the injection of the RSV standalone vaccine (Day 29)

Secondary outcomes

  1. hMPV serum anti-F immunoglobulin G (IgG) antibody (Ab) titers (Stage 1)

    Ab titers expressed as geometric mean titers (GMTs)

    Time frame: At pre-vaccination (Day 01) and 28 days (D29) post-primary vaccination

  2. RSV serum anti-F IgG Ab titers (Stage 1)

    Ab titers expressed as geometric mean titers (GMTs)

    Time frame: At pre-vaccination (Day 01) and 28 days (D29) post-primary vaccination

  3. hMPV A serum nAb titers (Stage 2 Expansion Cohort)

    Ab titers expressed as geometric mean titers (GMTs)

    Time frame: At pre-vaccination (Day 01), 28 days (D29), and 3 and 6 months post-primary vaccination

  4. hMPV B serum nAb titers (Stage 2 Expansion Cohort)

    Ab titers expressed as geometric mean titers (GMTs)

    Time frame: At pre-vaccination (Day 01), 28 days (D29), and 3 and 6 months post-primary vaccination

  5. hMPV A serum anti-F IgG Ab titers (Stage 2 Expansion Cohort)

    Ab titers expressed as geometric mean titers (GMTs)

    Time frame: At pre-vaccination (Day 01), 28 days (D29), and 3 and 6 months post-primary vaccination

  6. RSV A serum nAb titers (Stage 2 Expansion Cohort)

    Ab titers expressed as geometric mean titers (GMTs)

    Time frame: At pre-vaccination (Day 01), 28 days (D29), and 3 and 6 months post-primary vaccination

  7. RSV B serum nAb titers (Stage 2 Expansion Cohort)

    Ab titers expressed as geometric mean titers (GMTs)

    Time frame: At pre-vaccination (Day 01), 28 days (D29), and 3 and 6 months post-primary vaccination

  8. RSV serum anti-F IgG Ab titers (Stage 2 Expansion Cohort)

    Ab titers expressed as geometric mean titers (GMTs)

    Time frame: At pre-vaccination (Day 01), 28 days (D29), and 3 and 6 months post-primary vaccination

07

Study locations

24 sites
  • Velocity Clinical Research, Phoenix- Site Number : 8400025
    Phoenix, Arizona 85006, United States
  • CenExel CNS-Garden Grove- Site Number : 8400017
    Garden Grove, California 92845, United States
  • National Research Institute - Gardena- Site Number : 8400005
    Gardena, California 90247, United States
  • National Research Institute - Huntington Park- Site Number : 8400014
    Huntington Park, California 90255, United States
  • Velocity Clinical Research - San Diego- Site Number : 8400008
    La Mesa, California 91942, United States
  • Velocity Clinical Research Los Angeles- Site Number : 8400013
    Los Angeles, California 90017, United States
  • National Research Institute - Panorama City- Site Number : 8400012
    Los Angeles, California 91402, United States
  • Providence Clinical Research - North Hollywood- Site Number : 8400018
    North Hollywood, California 91606, United States
  • Peninsula Research Associates- Site Number : 8400002
    Rolling Hills Estates, California 90274, United States
  • Velocity Clinical Research - Denver- Site Number : 8400016
    Englewood, Colorado 80110, United States
  • Velocity Clinical Research - Washington DC- Site Number : 8400007
    Washington D.C., District of Columbia 20016, United States
  • Velocity Clinical Research - Hallandale Beach- Site Number : 8400022
    Hallandale, Florida 33009, United States
  • Suncoast Research Associates - Miami - Sunset Drive- Site Number : 8400001
    Miami, Florida 33173, United States
  • Velocity Clinical Research - Meridian- Site Number : 8400003
    Meridian, Idaho 83642, United States
  • Velocity Clinical Research - Kansas City- Site Number : 8400015
    Overland Park, Kansas 66210, United States
  • Velocity Clinical Research - Rockville- Site Number : 8400011
    Rockville, Maryland 20854, United States
  • Velocity Clinical Research - Lincoln - Valley Road- Site Number : 8400023
    Lincoln, Nebraska 68510, United States
  • Velocity Clinical Research - Omaha- Site Number : 8400006
    Omaha, Nebraska 68134, United States
  • Velocity Clinical Research - Springdale- Site Number : 8400004
    Cincinnati, Ohio 45246, United States
  • Velocity Clinical Research - Medford- Site Number : 8400024
    Medford, Oregon 97504, United States
  • Velocity Clinical Research - Austin- Site Number : 8400020
    Cedar Park, Texas 78613, United States
  • Velocity Clinical Research - Salt Lake City- Site Number : 8400010
    West Jordan, Utah 84088, United States
  • Velocity Clinical Research - Hampton- Site Number : 8400026
    Hampton, Virginia 23666, United States
  • Velocity Clinical Research - Seattle- Site Number : 8400019
    Seattle, Washington 98105, United States
08

References and documents

Individual participant data

Plan to share: Yes — Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Dec 11, 2025, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT06686654
Lead sponsor
Sanofi Pasteur, a Sanofi Company
Responsible party
Sponsor
First posted
Nov 13, 2024
Start date
Nov 11, 2024
Primary completion
Jan 18, 2027 (estimated)
Completion
Jan 18, 2027 (estimated)
Last update
Dec 11, 2025

Oversight

Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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